001/*
002 * (C) Copyright 2006-2016 Nuxeo SA (http://nuxeo.com/) and others.
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 *     http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 *
016 */
017package org.nuxeo.ecm.platform.preview.adapter.base;
018
019import java.io.File;
020import java.io.IOException;
021import java.io.InputStream;
022import java.util.List;
023
024import org.apache.commons.codec.digest.DigestUtils;
025import org.apache.commons.logging.Log;
026import org.apache.commons.logging.LogFactory;
027
028import org.nuxeo.ecm.core.api.Blob;
029import org.nuxeo.ecm.core.api.blobholder.BlobHolder;
030import org.nuxeo.ecm.core.api.blobholder.DocumentBlobHolder;
031import org.nuxeo.ecm.core.convert.api.ConversionException;
032import org.nuxeo.ecm.core.convert.api.ConversionService;
033import org.nuxeo.ecm.platform.mimetype.MimetypeDetectionException;
034import org.nuxeo.ecm.platform.mimetype.MimetypeNotFoundException;
035import org.nuxeo.ecm.platform.mimetype.interfaces.MimetypeRegistry;
036import org.nuxeo.ecm.platform.preview.adapter.MimeTypePreviewer;
037import org.nuxeo.ecm.platform.preview.adapter.PreviewAdapterManager;
038import org.nuxeo.ecm.platform.preview.api.NothingToPreviewException;
039import org.nuxeo.ecm.platform.preview.api.PreviewException;
040import org.nuxeo.runtime.api.Framework;
041
042/**
043 * Base class for preview based on "on the fly" HTML transformers
044 *
045 * @author tiry
046 */
047public class ConverterBasedHtmlPreviewAdapter extends AbstractHtmlPreviewAdapter {
048
049    private static final Log log = LogFactory.getLog(ConverterBasedHtmlPreviewAdapter.class);
050
051    protected String defaultFieldXPath;
052
053    protected MimetypeRegistry mimeTypeService;
054
055    public ConversionService getConversionService() {
056        return Framework.getService(ConversionService.class);
057    }
058
059    @Override
060    protected PreviewAdapterManager getPreviewManager() {
061        return Framework.getService(PreviewAdapterManager.class);
062    }
063
064    protected static String getMimeType(Blob blob) {
065        if (blob == null) {
066            return null;
067        }
068
069        String srcMT = blob.getMimeType();
070        if (srcMT == null || srcMT.startsWith("application/octet-stream")) {
071            // call MT Service
072            try {
073                MimetypeRegistry mtr = Framework.getService(MimetypeRegistry.class);
074                srcMT = mtr.getMimetypeFromFilenameAndBlobWithDefault(blob.getFilename(), blob,
075                        "application/octet-stream");
076                log.debug("mime type service returned " + srcMT);
077            } catch (MimetypeDetectionException e) {
078                log.warn("error while calling Mimetype service", e);
079            }
080        }
081        return srcMT;
082    }
083
084    protected String getMimeType(String xpath) {
085        BlobHolder blobHolder2preview = getBlobHolder2preview(xpath);
086        Blob blob = getBlob2preview(blobHolder2preview);
087        return getMimeType(blob);
088    }
089
090    protected String getDefaultPreviewFieldXPath() {
091        return defaultFieldXPath;
092    }
093
094    public void setDefaultPreviewFieldXPath(String xPath) {
095        defaultFieldXPath = xPath;
096    }
097
098    @Override
099    public List<Blob> getPreviewBlobs() throws PreviewException {
100        return getPreviewBlobs(getDefaultPreviewFieldXPath());
101    }
102
103    @Override
104    public boolean hasPreview(String xpath) {
105        String srcMT = getMimeType(xpath);
106        MimeTypePreviewer mtPreviewer = getPreviewManager().getPreviewer(srcMT);
107        return mtPreviewer != null || getConversionService().getConverterName(srcMT, "text/html") != null;
108    }
109
110    @Override
111    public List<Blob> getPreviewBlobs(String xpath) throws PreviewException {
112        BlobHolder blobHolder2preview = getBlobHolder2preview(xpath);
113        Blob blob2Preview = getBlob2preview(blobHolder2preview);
114
115        String srcMT = getMimeType(xpath);
116        log.debug("Source type for HTML preview =" + srcMT);
117        MimeTypePreviewer mtPreviewer = getPreviewManager().getPreviewer(srcMT);
118        if (mtPreviewer != null) {
119            return mtPreviewer.getPreview(blob2Preview, adaptedDoc);
120        }
121
122        String converterName = getConversionService().getConverterName(srcMT, "text/html");
123        if (converterName == null) {
124            log.debug("No dedicated converter found, using generic");
125            converterName = "any2html";
126        }
127
128        BlobHolder result;
129        try {
130            result = getConversionService().convert(converterName, blobHolder2preview, null);
131            setMimeType(result);
132            setDigest(result);
133            return result.getBlobs();
134        } catch (ConversionException e) {
135            throw new PreviewException(e.getMessage(), e);
136        }
137    }
138
139    /**
140     * @since 5.7.3
141     */
142    private Blob getBlob2preview(BlobHolder blobHolder2preview) throws PreviewException {
143        Blob blob2Preview = blobHolder2preview.getBlob();
144        if (blob2Preview == null) {
145            throw new NothingToPreviewException("Can not preview a document without blob");
146        } else {
147            return blob2Preview;
148        }
149    }
150
151    /**
152     * Returns a blob holder suitable for a preview.
153     *
154     * @since 5.7.3
155     */
156    private BlobHolder getBlobHolder2preview(String xpath) {
157        if ((xpath == null) || ("default".equals(xpath))) {
158            return adaptedDoc.getAdapter(BlobHolder.class);
159        } else {
160            return new DocumentBlobHolder(adaptedDoc, xpath);
161        }
162    }
163
164    protected void setMimeType(BlobHolder result) {
165        for (Blob blob : result.getBlobs()) {
166            if ((blob.getMimeType() == null || blob.getMimeType().startsWith("application/octet-stream"))
167                    && blob.getFilename().endsWith("html")) {
168                String mimeTpye = getMimeType(blob);
169                blob.setMimeType(mimeTpye);
170            }
171        }
172    }
173
174    protected void setDigest(BlobHolder result) {
175        for (Blob blob : result.getBlobs()) {
176            if (blob.getDigest() == null) {
177                try (InputStream stream = blob.getStream()) {
178                    String digest = DigestUtils.md5Hex(stream);
179                    blob.setDigest(digest);
180                } catch (IOException e) {
181                    log.warn("Unable to compute digest of blob.", e);
182                }
183            }
184        }
185    }
186
187    public String getMimeType(File file) throws ConversionException {
188        try {
189            return getMimeTypeService().getMimetypeFromFile(file);
190        } catch (ConversionException e) {
191            throw new ConversionException("Could not get MimeTypeRegistry");
192        } catch (MimetypeNotFoundException e) {
193            return "application/octet-stream";
194        } catch (MimetypeDetectionException e) {
195            return "application/octet-stream";
196        }
197    }
198
199    public MimetypeRegistry getMimeTypeService() throws ConversionException {
200        if (mimeTypeService == null) {
201            mimeTypeService = Framework.getService(MimetypeRegistry.class);
202        }
203        return mimeTypeService;
204    }
205
206    @Override
207    public void cleanup() {
208
209    }
210
211    @Override
212    public boolean cachable() {
213        return true;
214    }
215
216    @Override
217    public boolean hasBlobToPreview() throws PreviewException {
218        String xpath = getDefaultPreviewFieldXPath();
219        Blob blob2Preview;
220        try {
221            blob2Preview = getBlob2preview(getBlobHolder2preview(xpath));
222        } catch (NothingToPreviewException e) {
223            return false;
224        }
225        return blob2Preview != null;
226    }
227
228}